1. Field of the Invention
The invention relates to the transmission and reception of video over a wireless link. More specifically, the invention relates to the transmission and reception of high-definition video over a wireless link during varying link condition, by applying an unequal error protection to the video data.
2. Discussion of the Prior Art
In many houses, television and/or video signals are received through cable or satellite links at a set-top box at a fixed point in the house. In many cases, it is desired to place a screen at a point a distance from the set-top box by a few meters. This trend is becoming more common as flat-screen using plasma or liquid crystal display (LCD) televisions are hung on a wall. Connection of the screen to the set-top box through cables is generally undesired for aesthetic reasons and/or installation convenience. Thus, wireless transmission of the video signals from the set-top box to the screen is preferred. Similarly, it may be desired to place a computer, game controller, VCR, DVD, or other video source that generates images to be displayed on a screen a distance from the screen.
Generally, the data are received at the set-top box compressed in accordance, for example, with the motion picture expert group (MPEG) format and are decompressed by the set-top box to a high quality raw video signal. The raw video signal may be in an analog format or a digital format, such as the digital video interface (DVI) format or the high definition multimedia interface (HDMI) format. These digital formats generally have a high definition television (HDTV) data rate of up to about 1.5 Giga bits per second (Gbps).
Transmit a video image having such high bit rates it is necessary either to use sophisticated techniques for sending essentially uncompressed high-definition video or use a variety of compression technologies made available through standard or non-standard specification. A technique for sending essentially uncompressed high-definition video is described in detail in U.S. patent application Ser. No. 11/551,641, entitled Apparatus and Method for Uncompressed, Wireless Transmission of Video, assigned to a common assignee and incorporated herein in its entirety by reference thereto. Compression technologies include a variety of MPEG standard such as MPEG2, MPEG4, JPEG2000, wavelet technology, and the like. According to these technologies a transform is performed, for example a discrete cosine transform (DCT), resulting in a various coefficients representing the transformed image.
Wireless conditions may change over time, becoming worse or better, depending on a plurality of reasons. The changing conditions may result in a degradation of the video signal as conditions worsen. Regardless of the methods used above, it is well known that the coefficients generated by the variety of methods used have a varying degree of importance. For example, the coefficients representing lower spatial frequencies are more important for the creation of the reconstructed video at the receiver end than the coefficients representing the high spatial frequencies. Therefore, to ensure quality reception of wireless transmission of video, and, in particular, high-definition video it is important to ensure that as many of the lower-frequency coefficients as possible are received correctly.
In view of a variety of limitations of the prior art, it would be advantageous to provide a solution that enables reliable wireless transmission of high-definition video giving priority to the correct reception of those components of the transmission representing the higher importance components of the video image being transmitted.